(1.) Does black and white media exposure lead people to really dream in black and white or does it lead people to erroneously report that they do?

(2.) Do people who report dreaming in color really dream in color or are the colors of most of the objects in the dreamworld unspecified? (If you have trouble conceiving of the latter, think about novels, which leave the colors of most of their objects unspecified.)

Two recent studies (Schredl et al. 2008; Murzyn 2008) cast a bit more light on these questions. Both researchers asked general questions about people's dreams and also had people answer questions about their dreams in "dream diaries" immediately upon waking in the morning.

First, both studies confirm that college-age respondents these days rarely report black-and-white dreams, either when asked about their dreams in general or when completing dream diaries. Murzyn finds that older respondents (aged about 55-75 years) more commonly report black and white dreams, but even in this group the rates of reported black and white dreams (22%) don't approach the levels of 50 or 60 years ago.

On issue 1: Both Schredl and Murzyn find that people with better overall dream recall report more colored and less black and white dreaming. Schredl also finds that people with better recall of color in (waking) visual displays report more color in dreams. On the face of it, this might suggest that reports of black and white dreams come from less credible reporters; but it could just be that the kind of people who dream in black and white are the kind of people who dream less often and less vividly and are less interested in color memory tasks; or black and white dreams may generally be less detailed. Also, it's possible that the experimenters' different measures corrupt each other: People who describe themselves as having frequent colored dreams may find themselves more motivated to report richly detailed colored dreams and to try harder on color recall tasks (as if to conform to their earlier self-portrayal) than do those reporting black and white dreaming.

On issue 2: Both studies find that respondents generally claim to dream in color or a mix of color and black and white, rather than claiming to dream neither in color nor in black and white. In Murzyn's questionnaire, only one of sixty respondents claimed to dream neither in color nor black and white (which matches my own findings in 2003). In their dream diaries, Murzyn's participants described only 2% of their dreams as neither colored nor black and white. In Shredl's dream diaries, participants listed objects central to their dreams and stated if those objects were colored. By this measure, 83% of dream objects were colored (vs. 3% black and white, 15% don't recall). Therefore, if it's true that most dream objects are neither colored nor black and white, respondents themselves must not realize this, even about their own immediately past dreams. This may seem unlikely, but given the apparent inaccuracy of introspection even about current conscious experience I consider it a definite possibility.

Thursday, November 20, 2008

Psychologists -- and some philosophers -- spend a huge amount of time seeking grant money; I'm sure so also for many of the other sciences. I've become increasingly convinced that this is not the best way for leading researchers to be employing their time and talents. What if granting agencies simply selected (through a rotating committee of experts) a large number of established researchers and simply gave them research money without their having to ask, tracking only that it has been used for legitimate research purposes? There would still have to be ample room of course for unselected researchers to submit applications to obtain research funds and for researchers (selected or not) to submit applications for unusually large disbursements for especially worthy and expensive projects.

Wouldn't that give a lot of people more time simply to do their work?

Update, Nov. 21:Driving home after posting this yesterday, I found myself anticipating comments asserting that such a policy would increase the gap between the academic haves and have-nots. I think that's a legitimate concern, but one that could be addressed by having the granting committee be especially energetic about looking for merit in junior researchers and outside the top schools.

Friday, November 14, 2008

Do we have conscious sensory experience of objects we don't attend to? On a rich view, we have virtually constant sensory experience in every sensory modality (for example, all day long, a peripheral experience of the feeling of our feet in our shoes). On a thin view, conscious experience is limited to one or a few things or regions in attention at any given time. This rich-thin dispute is substantive, not merely terminological, and ordinary folks (as well as psychologists and philosophers) seem to split about 50-50 on it (with some moderates). I worry that the issue may be scientifically irresolvable.

However, some leading researchers in consciousness studies (Block 2007; and [more qualifiedly] Koch & Tsuchiya 2007) have recently put forward an argument against the thin view that runs as follows. When one's visual attention is consumed with a demanding task and stimuli are presented in the periphery, one can still report some features of those stimuli, such as their "gist" (e.g., animal vs. vehicle). Similarly, when one is presented with a Sperling-like display -- a very brief presentation of three rows of alphanumeric characters -- one has a sense of visually experiencing the whole display despite the fact that one can only attend to (and report) some incomplete portion of it. Therefore, conscious experience outruns attention.

I believe this argument fails. In both cases, it's plausible to suppose that there may be diffuse attention to the entire display, the entire (say) computer screen, albeit with focal attention on only one part of it. Such examples may establish that consciousness outruns focal attention narrowly defined, but they do not establish that consciousness outruns some broader span of diffuse attention. When attending to a visual display on a computer screen one may not even diffusedly attend to the picture on the wall behind the computer or the pressure of the seat against one's back. The question is, are these consciously experienced when absorbed in the experimental tasks? The Block/Koch argument shines no light whatsoever on that issue.

[Update November 19: Ned Block emailed me to say that he thinks I'm oversimplifying his view. I did simplify the argument somewhat, and for brevity and convenience I used the Sperling example, which he mainly deploys for another (closely related) purpose, rather than using his own preferred example. But whether the above is an objectionable oversimplification is a further question. I emailed Ned back hoping for clarification on some key points but have not yet received a reply.]

[Update November 20: Ned Block has emailed me with a fuller reply (full text, with his permission, here). He explains that in his view consciousness only probably outruns attention and that "the evidence points toward" that fact; and he thinks this is better suggested by "inattentional blindness" type cases (where people don't report seeing even fairly large objects or property changes when their attention is primarily occupied in some distractor task) than in what I called "Sperling-like" displays (by which I meant complex displays shown too briefly to allow full report but with report enabled by a cue to some portion of the display either during the display or very shortly thereafter). He also points out that Koch & Tsuchiya, like he, say that "it is difficult to make absolutely sure that there is no attention devoted to a certain stimulus". Finally, he says that to the extent he makes a case that consciousness outruns attention, it is a "holistic" case based on a variety of evidence and theoretical considerations, not a single type of experiment.

When I originally wrote the post, I was less interested in the details of Block interpretation than in a certain form of argument which I have heard several times orally (including during a well-attended talk by a very eminent researcher), the argument taking the form described in the post; and Block and Koch & Tsuchiya are the most eminent people I've found recently saying things along those lines in print; but it's true that I should have more carefully stated their qualifications and hesistations.]

Wednesday, November 05, 2008

David Lewis famously endorsed the possibility of "mad pain" in his article "Mad Pain and Martian Pain":

There might be a strange main who sometimes feels pain, just as we do, but whose pain differs greatly from ours in its causes and effects. Our pain is typically caused by cuts, burns, pressure, and the like; his is caused by moderate exercise on an empty stomach. Our pain is generally distracting; his turns his mind to mathematics, facilitating concentration on that but distracting him from anything else. Intense pain has no tendency whatever to cause him to groan or writhe, but does cause him to cross his legs and snap his fingers. He is not in the least motivated to prevent pain or get rid of it. In short, he feels pain but his pain does not at all occupy the typical causal role of pain.

Mad pain in this sense seems to me conceivable. My question is: Could there be a parallel case for belief? Let's try to imagine such a case.

Daiyu, say, is a woman who believes that most pearls are white. However, this belief was not caused in the normal way. It was not caused by having seen white pearls nor by hearing testimony to the effect that most pearls are white or inferring that pearls are white from some other facts about pearls or whiteness. It was caused, say, by having looked for 4 seconds at the sun setting over the Pacific Ocean. And, for her, this is just the kind of event that would cause that belief: It's not the case that she would ever form that belief by any of the normal means such as those described above; rather the kinds of things that cause that belief in her in all "nearby possible worlds", or across the relevant range of counterfactual circumstances, are perception of setting-sun events of a certain sort, and maybe also eating a certain sort of salad. Furthermore, Daiyu's belief that most pearls are white has atypical effects. It does not cause her to say anything like "most pearls are white" (which she'd deny; she is actually disposed to say "most pearls are black") or to think to herself in inner speech "most pearls are white". She would feel surprise were she to see a white pearl. If a friend were to say she was looking for white jewelry to go with a dress, Daiyu would not be at all inclined to recommend a pearl necklace. She is not at all disposed to infer from her belief that most pearls are white that there is a type of precious object used in jewelry that is both round and white.

Now I'm inclined to think that this case is incoherent. If Daiyu in fact has that sort of causal/functional structure, it's not correct to say that she really does believe that most pearls are white. In this respect, belief is different from pain. If you agree with me about this, that would seem to rule out a certain class of views about belief, namely, those views that characterize belief in terms of a mental state (maybe a brain state) of the sort that, in humans, typically has certain sorts of causes and typically has certain sorts of effects but which may, in some particular individuals, be not at all apt to have been brought about those causes and be not at all apt to have those effects. It's hard to know exactly how to read "representationalists" about belief (like Fodor, Dretske, Millikan) on this point, but a certain way of reading the representationalist view would imply no incoherence in the idea of mad belief: If an individual possesses an internal representation of the right sort, held in such a way that if everything were functioning normally it would have the normal effects, that person believes -- even if everything is not functioning normally.

Compare: having a heart. Hearts might be defined in terms of their normal functional role (to pump blood), but a being can still have a heart even if that heart fails utterly to fill that normal functional role (in which case the being will presumably either not be viable or have its life sustained somehow without a functioning heart). I'm a type functionalist about hearts: To have a heart is to have the type of organ that normally fills the causal role of hearts even if in one's own case the organ does not fill that causal role. Lewis is a type functionalist about pain. But if the Daiyu case is incoherent, we should not be type functionalists about belief. Closer to the truth, I suspect, would be token functionalism: To believe is to be in a state that actually, for you, plays the functional/causal role characteristic of belief. I'm not sure how readily representationalists about belief, especially those who think of mental representations as biological types or real in-the-head entities, can take token functionalism on board. Perhaps they are committed to the possibility of mad belief.